This invention relates to fuel control systems for gas turbine engines, and more particularly to fuel control systems which embody a metering pump driven by a variable speed drive mechanism.
U.S. patent application Ser. No. 433,229, filed Jan. 14, 1974, now U.S. Pat. No. 3,908,360, and entitled "Pump Metering Fuel Control System" shows a fuel control system which incorporates a metering pump driven by a variable speed drive mechanism. The pressure rise across the pump is controlled by a head regulator so that the output flow thereof is essentially a linear function of pump speed, the back pressure variation not influencing fuel flow. When coupled with a closed loop speed control for the pump, such an arrangement permits open loop scheduling of acceleration and deceleration fuel flow to yield accurately metered flows.